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36 votes

Why do unfinished basements need GFCI outlets?

Even "dry" concrete contains considerable water, and is a relatively good conductor. So, it's a relatively good path to ground for a person touching it, increasing the odds of a lethal shock. ...
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  • 137k
34 votes

Is it OK to create a third prong ground from a cold water pipe, for a 2-wire circuit?

When or is it NEC code compliant to upgrade a 2-wire circuit, by adding a third prong equipment ground from a nearby galvanized cold water pipe? Never! Article 250.118 of the National Electrical ...
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  • 19.4k
29 votes

Why does US Code not allow a 15A single receptacle on a 20A circuit?

Let me give some framework around what ThreePhaseEel said. I can understand wondering that, since UK appliances all have fuses in their plugs, and I bet the fuses are sized to protect the appliance. ...
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28 votes
Accepted

Why does US Code not allow a 15A single receptacle on a 20A circuit?

The key lies in the way UL tests 15A and 20A receptacles Answering this question requires a deep dive into the standard UL tests 15A and 20A receptacle devices to, namely UL 498. In particular, we ...
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24 votes
Accepted

Can I run stripped Romex/NM through conduit?

The wires in NM aren't labeled for use outside the cable jacket, and may not be the correct type for use in conduit to begin with First off, the wires inside a NM cable are not marked or labeled at ...
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23 votes
Accepted

Can I legally add an outlet with 2 screws when the previous outlet was passthough with 4 screws?

Adding the short wire is called pigtails and it is code compliant so yes you can do this. Pigtails are a superior way of making connections in my opinion. The pigtails do not add to the wire volume in ...
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22 votes

Can I legally add an outlet with 2 screws when the previous outlet was passthough with 4 screws?

The most important rule in NEC is 110.3(B), which requires you to follow labeling and instructions... which means read them. In this case, that only makes things better, particularly the boldface in ...
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17 votes

Is this wiring safe and is it according to code?

There is one safety issue here It appears that the original installer took the ground wire from the 12/3 cable, looped it around one switch ground screw, then attached it to the other switch ground ...
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17 votes

What range of heights are allowed for wall receptacles?

The NEC doesn't count a receptacle above 5-1/2' to satisfy the requirement - 210.52(4) Located more than 1.7 m (51⁄2 ft) above the floor The NEC doesn't have a lower limit for height, in fact 210....
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16 votes

How should I mount conduit to my wood-laped siding?

Those hangers will stick out and potentially catch on clothing. I would use saddles.
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  • 13.8k
15 votes

Why do unfinished basements need GFCI outlets?

You don't need GFCI receptacles anywhere. Nobody cares how you provision the GFCI protection. You are welcome to have one GFCI device and feed all the receptacles from the protected zone (LOAD) of ...
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13 votes

Best way to cover exposed THHN cables where conduit has been pulled out

The conduit entering the box evidently needed, but someone thought it didn't need, an expansion fitting. They appear to have also skipped glue, as I don't see any remains of glue or broken conduit in ...
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  • 137k
12 votes
Accepted

Does electrical code allow NEMA 14-60R receptacles in residential settings?

You can have a 14-60R in your house, but it must be on a dedicated branch circuit There is nothing in the NEC that prohibits you from having a 60A (or larger!) receptacle in your house. (While NEMA-...
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12 votes
Accepted

Can I run my three-way travelers in a 14/2 without a neutral in the cable?

This is not allowed because it violates the rule that in any cable there must be two conductors carrying equal current in opposite directions so the magnetic fields cancel. That T- T Loop top right ...
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12 votes
Accepted

Will this electric panel pass NC inspection?

The clearance requirement is almost definitely going to be an issue. (And not an unusual issue - I will have the same problem if/when I ever upgrade my panel and get it inspected.) The shelves should ...
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12 votes

When running a bigger wire to deal with voltage drop on a 240V circuit, do I now need to run a neutral as well?

My question is now that I'm running a 30 amp wire and only using 20 amps, do I need to run a neutral to send the unused 10 amps back the supply? There is no 'unused 10 A'. However (and this is ...
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12 votes
Accepted

Does the NEC require cable to not be twisted?

There are no requirements to not twist the wire, and this is especially difficult to ensure when fishing wire without staples as allowed in “old work” installations. To fully answer the general ...
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11 votes

Why aren't AFCI breakers required for bathrooms/lavatories?

We're reading tea leaves here to guess at NFPA's intent. NFPA writes the "model electrical code" which they offer for anyone in the world to adopt as their law. But politically, NFPA has been ...
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11 votes
Accepted

Are GFCI outlets allowed on new circuit installations?

The Code doesn't specify location of protection. NEC 2017 210.8 Ground-Fault Circuit-Interrupter Protection for Personnel. Ground-fault circuit-interrupter protection for personnel shall be provided ...
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11 votes
Accepted

How should I mount conduit to my wood-laped siding?

For EMT (anyway) the spacing is pretty clear - I can't recall if it's the same or different for other types, but it might well be the same. Within 12" of each box. 10 feet maximum spacing (1 ...
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  • 137k
10 votes
Accepted

How do I properly place devices in an electrical enclosure?

Enclosure You start with an enclosure that includes a backplate (interior panel) -- usually this is purchased separately from the enclosure itself, but the manufacturers make sizes that fit mounting ...
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  • 28.3k
10 votes
Accepted

OK to bundle wires together with colored electrical tape?

It's mandatory When putting identical-appearing circuits in a conduit, you must differentiate them somehow. It's mandatory. I would not bundle them but mark them individually. Black(blue) and ...
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10 votes

Can I run #14 armored cable behind baseboards?

NEC 300.4(D) covers the type of installation indicated in the question, and it applies to both AC and MC armored cable. So you'll need to use a steel guard at least 1/16" thick to protect the cable. ...
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10 votes
Accepted

Why are 120 V general receptacle circuits limited to 20 A?

Why 20A? Receptacle design constraints, most likely The reason why general receptacle circuits top out at 20A is because the notion of a duplex receptacle doesn't work for larger plug sizes (just can'...
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10 votes

Any way to meet code with 40.7% or 40.44% conduit fill?

Derailed by Derating Your plan is a non-starter, even if you overcome the fill issues you're having, because of the other limit the NEC places on conduit fill; namely, the derating factors found in ...
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10 votes

How do you comply with NEC receptacle requirements in row homes with brick walls?

I see two options. What I see in the US quite a bit is instead of running the plastic channels on the wall surface, people will use steel conduit. It gives kind of a rustic/industrial look. ...
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10 votes

Using NEMA 14-50 with 60A breaker

No philosophy: Code is data-driven Code is the result of analysis of systematically collected data about actual electrical accidents as they happened in the field. It’s the nature of science that ...
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10 votes

Is UL/NRTL listing the only criterion for permitting direct-wiring into a junction box?

FreeMan nailed it. You must follow the entire electrical code. You're focusing on 110.2 but actually, you must follow the entire electrical code. If you read the rest of it, eventually you will reach ...
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9 votes
Accepted

How is "continuous wiring" defined in context of the 2017 NEC code?

Nope. Nope nope nope. You cannot use 210.12(A)(4) to put AFCI at an outlet. There are certain fairly rare cases where you can put AFCI at the first outlet. However, there is a misconception that ...
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9 votes

Should I keep this surge suppressor in my main load center?

They are intended to be mounted outside the box... You are correct that they are intended to be mounted to a KO (usually on the breaker box), instead of being left inside, all flop-a-dop, as yours was....
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